Energy absorbing blast wall for building structure

ABSTRACT

A wall system protects a building structure from pressure caused by explosive blasts. The wall system includes vertical studs. Outer blast wall panels and inner blast wall panels are secured to the opposing sides of the vertical studs. An upper mounting system is attached to the building structure. An upper mounting system includes a fixed track, a movable mounting track, and an energy absorbing system that flexibly couples the movable mounting track to the fixed track. The upper ends of the vertical studs are attached to movable mounting track. A lower mounting system includes a mounting track that aligns the lower ends of the vertical studs. The wall is filled with an energy absorbing material. The lower ends of the vertical studs are connected to a lower track.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/113,911 filed on May 23, 2011, which claims the benefit of priorityunder 35 USC §119(e) to U.S. Provisional Application No. 61/380,703filed on Sep. 7, 2010, and to U.S. Provisional Application No.61/437,628 filed on Jan. 29, 2011. U.S. patent application Ser. No.13/113,911 is also a continuation-in-part of U.S. patent applicationSer. No. 12/336,524 filed on Dec. 16, 2008, which claims the benefit ofpriority under 35 USC §119(e) to U.S. Provisional Application No.61/015,195 filed on Dec. 20, 2007. U.S. patent application Ser. No.12/336,524 issued on Dec. 20, 2011, as U.S. Pat. No. 8,079,188.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally in the field of protective wallstructures for buildings, and, more particularly, is in the field ofblast resistant walls.

2. Description of the Related Art

Current existing blast resistant wall assemblies attempt to resist theextreme forces generated by explosives with massively heavy and verycostly components. The wall components endeavor to remain in place whenimpacted by a blast wave. If the wall components fail, the componentsare propelled into the interior space of the structure to damageequipment and harm people that the wall components are intended toprotect.

SUMMARY OF THE INVENTION

A blast wall assembly and the components described herein form anintegrated system that effectively absorbs blast energy. Unlikeconventional systems, the components of the blast wall assembly functionin a manner similar to highway “crumple zones” by absorbing the energygenerated by the sudden impact of a blast wave on the exterior surfaceof the blast wall. The components of the blast wall assembly flex, move,compress, crush and bend before the full magnitude of the blast load istransmitted via the components to the fasteners used to secure theassembly to the structure. By absorbing the sudden impact of energy, thesystem greatly reduces the likelihood of component failure and fastenerfailure. Although the blast wall assembly may incur repairable damage,the blast wall assembly absorbs a substantial portion of the blastenergy rather than imploding into the interior space of the structure.Thus, the blast wall assembly greatly enhances the safety of thebuilding structure and the occupants of the building structure.

When a blast pressure wave first impacts an exterior blast board, theexterior blast board resists penetration by objects, such as rocks andshrapnel, which may be hurled against the wall by the blast force. Aportion of the energy of the blast wave is absorbed by flexural bendingof the exterior blast board. The load applied to the exterior blastboard by the blast pressure wave is transferred to vertical wall studs.The exterior blast board also provides lateral bracing for the verticalstuds, which helps prevent torsional failure of the light gauge verticalstuds. The exterior blast board also serves as a substrate for a varietyof exterior finish systems that may be applied to the cementitious wallboard forming the outer face of the exterior blast board. Thus, from theoutside, the blast wall assembly may be configured to have the cosmeticappearance of a conventional wall.

The light gauge (e.g., 16 gauge) vertical wall studs are flexible. Thus,when the load from the blast pressure wave is applied to the wall studsvia the outer blast pane, the wall studs bend and deform and eventuallystretch. The magnitude of deformation of the wall studs may exceed theyield strength of the wall studs and cause a portion of the deformationto be permanent. The bending, deformation and stretching of the studsabsorbs additional blast energy.

As each vertical wall stud deforms inward away from the blast force, thestud has a tendency to pull out of an upper mounting channel (track) anda lower mounting channel (track) that constrain the upper end and thelower end, respectively, of each stud. An angle clip at the top of eachvertical stud and an angle clip at the bottom of each stud resist thispull-out force while simultaneously absorbing blast energy. As thevertical stud deflects inwardly, the chord distance between the top endand the bottom end of the stud shortens. The angle clips have horizontallegs that deform by bending in response to the tensile force thatattempts to straighten the angle clips. The deformations of the angleclips absorb additional blast energy.

When the bottom angle clip deforms, the tendency of the bottom angleclip to straighten is resisted by a bottom energy absorbing pad. Thebottom energy absorbing pad is compressed vertically as the horizontalleg attempts to pull away from the lower mounting channel. Thecompression of the bottom energy absorbing pad absorbs additional blastenergy. A metal plate laminated to the top of the bottom energyabsorbing pad helps prevent the pad from pulling over an anchor bolt atthe bottom of the wall and prevents the pad from being crushed by ahexagonal nut that secures the pad to the bottom attachment anchor bolt.

The bottom energy absorbing pads at the bottoms of the wall studs alsoabsorb energy while allowing the entire base of the wall to move inwardaway from the blast. As described herein, the bottom mounting channel(or track) and the bottom clips include respective slots (or oversizedholes) that permit the entire lower portion of the blast wall assemblyto move inward away from the blast force until reaching the end of theslot or the boundary of the oversized hole. The bottom energy absorbingpads prevent the wall from moving too quickly and applying a shock loadto the lower anchor bolts. When the bottom energy absorbing padscompress under load, the pads create a more gradual (cushioned) increasein the load to the wall anchors. Thus, the bottom energy absorbing padshelp preserve the integrity of the critical attachment of the wall tothe building structure.

An upper mounting system and an upper energy absorbing assembly at thetop of the blast wall assembly absorb blast energy and resistdestructive movement caused by the blast energy. The upper mountingsystem and the upper energy absorbing assembly also permit the floorabove the blast wall assembly to deflect vertically in response tochanging live loads to the floor above the wall, the floor below thewall or both. The floating configuration of the upper mounting allowsdeflections to occur without transferring axial loads (e.g., bearingloads) to the wall. The blast wall assembly disclosed herein can be usedas either a non-bearing partition wall or as a curtain wall.

When a top angle clip deforms, the tendency of the clip to straighten isreduced by the bending of a horizontal flange stud that spans thedistance between adjacent upper mounting systems. The tensile forcecaused by a blast causes the angle clip to bend (e.g., straighten) andinduces weak axis bending in the horizontal flange stud. The horizontalflange stud also provides an engagement between the vertical wall studsand an upper blast track. In particular, the outer surfaces of thevertical walls of the horizontal flange stud ride may float up or downwithin the cavity formed by the upper blast track. The floatingengagement between the horizontal stud and the upper blast track isconfigured to reduce the effect of the blast forces. As describedherein, the top angle clip and the horizontal flange stud are nested sothat the side walls of the horizontal flange stud are unobstructedwithin the upper blast track to thereby accommodate vertical movementbetween the floor above and the wall below. Additional blast energy isabsorbed by bending of the horizontal stud flange and bending of theflange of the upper blast track on the side of the wall opposite theblast. Both components bend in a direction normal to the plane of thewall.

Lateral movement of the blast wall assembly in a direction normal to thewall plane is primarily resisted by bending of a down-turned flange ofthe upper blast track. As each vertical stud bends, the chord distancebetween the upper and lower ends of the vertical stud shortens asdiscussed above. A spring or other elastic member in the upper energyabsorption assembly compresses to absorb blast energy. Once the springin the energy absorbing assembly is fully compressed, a threaded steelrod in the assembly transmits tensile loads to the upper blast trackthrough the anchor wedge washer. As the wall deforms inward, thethreaded rod pivots to transfer tensile load and shear load to the upperblast track, which causes the upper blast track to deform in thevicinity of the wedge washer. The deformation of the upper blast trackabsorbs more blast energy.

Once the blast load is transferred to the upper blast track by bendingthe outer wall (flange of the upper blast track) and by the upper energyabsorption assembly, the transferred load is transferred to the buildingstructure by way of an upper anchor bolt embedded in a header. The forcetransferred to the upper anchor bolt is cushioned by the deformation ofa trapezoidal channel in the upper blast track and by the verticalflange and weak axis bending of a U-shaped blast track anchor channel.The shape of the blast track in combination with the blast track anchorchannel results in a more gradual transfer of forces to the topconnection, which helps preserve the integrity of the top connection andof the blast wall assembly.

The blast wall assembly further comprises an interior blast board. Eachpanel of the interior blast board comprises a layer of metal and aninterior finish wall board to form a generally rectangular sheet. In apreferred embodiment, the interior blast board is fabricated with ametal flange extending along one of the long edges. The long edges areoriented horizontally in the preferred embodiments. The metal flangeallows the interior sheathing to be spliced to the adjacent sheathing(the inner blast panel immediately above). The splice effectivelyconnects the upper and lower sheathing boards to form a continuousprotective curtain reaching from the top to the bottom of the wall. Ifone or more sheets become dislodged, the dislodged sheets remain inplace on the wall and pose no hazard to the building occupants.Preferably, the sheets are positioned on the wall with the locations ofthe splices staggered so that the splices do not coincide with theutility punch outs in the vertical studs of the wall. Thus, the interiorblast board reinforces the wall and helps prevent stud failure at theutility punch-outs. Furthermore, the metal lined interior blast boardsprovide torsional restraint for the vertical studs to effectivelyprevent torsional failure of the vertical studs. In alternativeembodiments, the interior blast board may be oriented vertically, andmay be constructed without the extended metal flanges.

In accordance with another embodiment disclosed herein, a wall systemfor protecting a building structure from pressure caused by explosiveblasts, comprises a plurality of vertical studs having respective upperends and lower ends. At least one outer blast wall panel is secured tothe vertical studs to form an outer wall of the wall system. At leastone inner blast wall panel is secured to the vertical studs to form aninner wall of the wall system. An upper mounting system is attached tothe building structure, and the upper ends of the vertical studs areattached to the upper mounting system. A lower mounting system isattached to the building structure, and the lower ends of the verticalstuds attached to the lower mounting system. At least one cavity isformed between the at least one outer blast wall and the at least oneinner blast wall, and an energy absorbing material substantially fillsthe at least one cavity.

In certain embodiments of the wall system, the energy absorbing materialcomprises expanded polystyrene foam.

In certain embodiments of the wall system, each vertical stud extendsfrom the at least one outer blast wall panel to the at least one innerwall panel.

In other embodiments of the wall system, each vertical stud ispositioned to be attached to only the at least one inner blast wallpanel or to only the at least one outer blast wall panel. For example,the vertical stud attached to the at least one inner blast wall panelcomprises a U-channel stud having a web and a respective flange at eachedge of the web; and the at least one inner blast wall panel isconnected to the web of the vertical stud with the flange at each edgeof the web extending into the energy absorbing material in the cavity.Similarly, the vertical stud attached to the at least one outer blastwall panel comprises a U-channel stud having a web and a respectiveflange at each edge of the web; and the at least one outer blast wallpanel is connected to the web of the vertical stud with the flange ateach edge of the web extending into the energy absorbing material in thecavity.

Alternatively, the vertical stud attached to the at least one innerblast wall panel comprises a C-stud having a web, a respective flange ateach edge of the web, and a respective lip perpendicular to each flange,and the at least one inner blast wall panel is connected to the web ofthe vertical stud with the flange at each edge of the web extending intothe energy absorbing material in the cavity, and with each lip embeddedin the energy absorbing material. Similarly, the vertical stud attachedto the at least one outer blast wall panel comprises a C-stud having aweb, a respective flange at each edge of the web, and a respective lipperpendicular to each flange; and the at least one outer blast wallpanel is connected to the web of the vertical stud with the flange ateach edge of the web extending into the energy absorbing material in thecavity, and with each lip embedded in the energy absorbing material.

In accordance with certain embodiments, a wall system for protecting abuilding structure from pressure caused by explosive blasts comprises aninner blast wall panel having a generally rectangular metal sheet and aninterior wall board laminated to the metal sheet. The inner blast wallpanel is secured to vertical studs with the metal sheet positionedagainst the vertical studs and with the interior wall board facing awayfrom the vertical studs. The wall system further includes an outer blastwall panel having a generally rectangular metal sheet and an exteriorwall board laminated to the metal sheet. The outer blast wall panel issecured to vertical studs with the metal sheet positioned against thevertical studs and with the exterior wall board facing away from thevertical studs. An energy absorbing material is positioned between theinner blast panel and the outer blast panel. In certain embodiments, thewall system is mounted between an upper header and a lower footer. Inother embodiments, the wall system is mounted to an outer face of astructure to span between two floors of the structure as a curtain wall.In a particular configuration of the wall system, the inner blast paneland the outer blast panel are secured to opposing flanges of studs thatextend through the energy absorbing material between the inner blastpanel and the outer blast panel. In another configuration of the wallsystem, the inner blast panel is secured to a first set of studs, andthe outer blast panel is secured to a second set of studs, wherein thefirst set of a studs and the second set of studs separated by the energyabsorbing material.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other aspects of this disclosure are describedin detail below in connection with the accompanying drawing figures inwhich:

FIG. 1 illustrates a perspective view of a blast wall installed betweenan upper concrete header and a lower concrete footer with respectiveportions of the header and footer removed to show the mounting anchorbolts;

FIG. 2 illustrates an enlarged cross-sectional elevational view of aportion of the upper concrete header, the mounting tracks, the upperends of two vertical studs and an energy absorption assembly between thevertical studs viewed in the direction of the lines 2-2 in FIG. 1;

FIG. 3 illustrates an enlarged cross-sectional elevational view of aportion of the lower concrete footer, the bottom track, the lower endsof two vertical studs and the energy absorption pad viewed in thedirection of the lines 3-3 in FIG. 1;

FIG. 4 illustrates an elevational cross-sectional end view of the blastwall of FIG. 1 in the direction of the lines 4-4 in FIG. 1 that showsthe attachment structures at the top and bottom portions of an exemplaryvertical stud and which further shows the structure of the inner blastpanel (to the left in FIG. 4) and the outer blast panel (to the right inFIG. 4);

FIG. 5 illustrates an enlarged cross-sectional elevational end view ofthe top portion of the vertical wall stud of FIG. 4 bounded by thecircular area 5 in FIG. 4;

FIG. 6 illustrates an enlarged cross-sectional elevational end view ofthe bottom portion of the vertical wall stud of FIG. 4 bounded by thecircular area 6 in FIG. 4;

FIG. 7 illustrates an enlarged cross-sectional elevational end view inthe direction of the lines 7-7 in FIG. 1 that shows the energyabsorption system that couples the upper blast track to the floatingblast wall;

FIG. 8 illustrates an enlarged cross-sectional view of a portion of theoverlap of an upper inner blast panel with respect to a tab extendingupward from a lower inner blast panel which is bounded by the circulararea 8 in FIG. 4;

FIG. 9 illustrates an enlarged cross-sectional view in the direction ofthe lines 9-9 in FIG. 1 to show the mounting of the inner blast paneland the outer blast panel to the upper mounting channel (track);

FIG. 10 illustrates a perspective view of the blast track anchor channelmounted to the upper anchor bolt;

FIG. 11 illustrates an end elevation view of the blast track anchorchannel and the upper anchor bolt of FIG. 10;

FIG. 12 illustrates an enlarged perspective view of the blast energyabsorption assembly of FIG. 7;

FIG. 13 illustrates an end elevation view of the blast energy absorptionassembly of FIG. 12;

FIG. 14 illustrates a perspective view of the upper stud attachment clipof FIG. 5;

FIG. 15 illustrates a perspective view of the lower stud attachment clipof FIG. 6;

FIG. 16 illustrates an exploded perspective view of the elastomer blockand the metal plate of the energy absorption pad of FIG. 6

FIG. 17 illustrates a perspective view of the assembled energyabsorption pad of FIG. 6;

FIG. 18 illustrates a perspective view of the upper blast track of FIG.1 to show the holes for mounting the upper blast track to the upperconcrete header and showing the holes for mounting the energy absorptionassembly to the blast track;

FIG. 19 illustrates an end elevational view of the upper blast track ofFIG. 18 to show a preferred cross section for the upper blast track;

FIG. 20 illustrates a perspective view of the upper horizontal stud ofFIG. 1 mounted to the upper mounting channel (track) of FIG. 1 to showthe holes for mounting the energy absorption assembly and to show thepilot holes for mounting the upper stud attachment clip of FIG. 14;

FIG. 21 illustrates an end elevational view of the joined upperhorizontal stud and upper channel of FIG. 20 to show preferred crosssections for the joined components;

FIG. 22 illustrates a perspective view of the lower mounting channel(track) of FIG. 1 to show the slotted holes for attaching the lowermounting channel to the lower concrete footer;

FIG. 23 illustrates an end elevational view of the lower mountingchannel of FIG. 22 to show a preferred cross section for the lowermounting channel;

FIG. 24 illustrates a perspective view of portion of a wall section inaccordance with a further embodiment of an energy absorbing blast wallin which the cavity between inner and outer blast panels mounted onC-studs is substantially filled with an energy absorbing material, andin which the wall section is coupled to the building by the energyabsorbing track assemblies;

FIG. 25 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 24 viewed in the direction of the lines 25-25 inFIG. 24;

FIG. 26 illustrates a perspective view of portion of a wall section inaccordance with FIG. 24 in which the wall section is coupled to thebuilding by a fixed track assembly;

FIG. 27 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 26 viewed in the direction of the lines 27-27 inFIG. 26;

FIG. 28 illustrates a perspective view of portion of a wall section inaccordance with a further embodiment of an energy absorbing blast wallin which the cavity between inner and outer blast panels mounted on thewebs of respective sets of U-channel studs is substantially filled withan energy absorbing material, and in which the wall section is coupledto the building by the energy absorbing track assemblies;

FIG. 29 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 28 viewed in the direction of the lines 29-29 inFIG. 28;

FIG. 30 illustrates a perspective view of portion of a wall section inaccordance with FIG. 28 in which the wall section is coupled to thebuilding by a fixed track assembly;

FIG. 31 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 30 viewed in the direction of the lines 31-31 inFIG. 30;

FIG. 32 illustrates a perspective view of portion of a wall section inaccordance with a further embodiment of an energy absorbing blast wallin which the cavity between inner and outer blast panels mounted on thewebs of respective sets of C-studs is substantially filled with anenergy absorbing material, and in which the wall section is coupled tothe building by the energy absorbing track assemblies;

FIG. 33 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 32 viewed in the direction of the lines 33-33 inFIG. 32;

FIG. 34 illustrates a perspective view of portion of a wall section inaccordance with FIG. 32 in which the wall section is coupled to thebuilding by a fixed track assembly;

FIG. 35 illustrates an enlarged cross-sectional plan view of the portionof the wall in FIG. 34 viewed in the direction of the lines 35-35 inFIG. 34;

FIG. 36 illustrates a perspective view of the wall section of FIG. 34mounted as part of a curtain wall;

FIG. 37 illustrates an enlarged cross-sectional plan view of the portionof the wall corresponding to the cross-sectional plan view of FIGS. 33and 35 wherein the C-studs are replaced with modified studs;

FIG. 38 illustrates an enlarged cross-sectional plan view of the wallsection corresponding to the wall section of FIG. 37 but with the studscoupled to the inner blast panels aligned with the studs coupled to theouter blast panels;

FIG. 39 illustrates a perspective view of a blast wall similar to theblast wall of FIG. 1 modified with a lower track (channel) havingintegral tabs for connecting to the vertical studs, wherein portions ofthe inner and outer blast panels are removed to show the lower end ofone of the vertical studs;

FIG. 40 illustrates an enlarged perspective view of the bottom portionof the blast wall of FIG. 39 bounded by the circular area 40 in FIG. 39;

FIG. 41 illustrates a perspective view of the initial construction ofthe lower channel of FIGS. 39 and 40 showing the generally U-shaped slotand the pilot hole formed in the webbing of the lower track at intervalscorresponding to the stud spacing;

FIG. 42 illustrates an enlarged perspective view of the portion of thelower track of FIG. 41 bounded by the area 42 in FIG. 41;

FIG. 43 illustrates a perspective view of the second stage ofconstruction of the lower track of FIG. 41 showing the tabs bent upwardfrom the webbing to a position substantially perpendicular to thewebbing;

FIG. 44 illustrates an enlarged perspective view of the portion of thelower track of FIG. 43 bounded by the area 44 in FIG. 43;

FIG. 45 illustrates a perspective view of a blast wall similar to theblast wall of FIG. 1 that mounts the lower stud attachment clip directlyto the webbing of the lower track and that includes a plate to securethe webbing of the lower track to a mounting anchor bolt, whereinportions of the inner and outer blast panels are removed to show thelower end of one of the vertical studs; and

FIG. 46 illustrates an enlarged perspective view of the bottom portionof the blast wall of FIG. 45 bounded by the circular area 46 in FIG. 45.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates a perspective view of a blast wall 100. The blastwall comprises a blast wall assembly 110 installed between an upperheader 112 and a lower footer 114. In the illustrated embodiment, theheader and the footer comprise concrete; however, the header, the footeror both may comprise other suitable materials. In the illustratedembodiment, the blast wall assembly is secured to the header and thefooter by a plurality of upper anchor bolts 120 (one of which is shownin the broken section of the header) and a plurality of lower anchorbolts 122 (one of which is shown in the broken section of the footer).In the illustrated embodiment, the upper anchor bolts are advantageouslyspaced apart by approximately 24 inches and the lower anchor bolts areadvantageously spaced apart by 16 inches. In other configurations, thedistances between the anchor bolts may be different.

As further shown in FIG. 1, the blast wall assembly 110 comprises aplurality of inner blast panels (interior blast boards) 130 and aplurality of outer blast panels (exterior blast boards) 132 mounted on aplurality of vertical wall studs 134. The vertical studs advantageouslycomprise conventional light gauge metal studs having a C-shaped crosssection. For example, in the illustrated embodiment, each metal stud hasa main body portion having an outside width of approximately 4 inches,has opposing side walls that extend approximately 2 inches perpendicularto the main body portion, and has flanges that extend inwardlyperpendicular to the side walls for approximately ½ inch. In oneembodiment, each metal stud comprises 16 gauge steel having a thicknessof approximately 1/16 inch. The width of the main body of each stud maybe increased to increase the overall thickness of the blast wallassembly. The vertical studs are advantageously spaced apart by aconventional distance. In the illustrated embodiment, the vertical studsare spaced apart by approximately 16 inches. For additional wallstrength, the vertical studs may be spaced apart by 12 inches, forexample.

As further shown in FIG. 1, the upper end of each vertical stud 134 ismounted to an upper mounting track (channel) 140, which isadvantageously a modified conventional mounting channel for ametal-framed building. For example, as shown in FIGS. 20 and 21, theupper channel advantageously comprises 16 gauge steel formed into agenerally U-shaped profile having a base portion with an inner width ofapproximately 4 inches between two perpendicular side walls. Inparticular, the inner width of the upper channel is sized to accommodatethe outer width of each vertical stud. Accordingly, for thicker wallshaving vertical studs with a greater base size, the inner width of thebase of the upper channel is increased accordingly. In the illustratedembodiment, the side walls have lengths of approximately 1.5 inches. Theopen face of the U-shaped profile is positioned fastened downwardly toreceive the upper end of each vertical stud.

Unlike an upper channel in a conventional metal-framed wall structure,the upper mounting channel 140 in FIG. 1 is not fixedly attached to theupper header 112. Rather, as described below in more detail, the upperchannel is mounted to an upper horizontal stud 142, which advantageouslycomprises a conventional C-shaped framing stud positioned horizontallyrather than vertically. In the illustrated embodiment, the horizontalstud has a profile and dimensions that correspond to the profile anddimensions of the vertical studs 134 as described above. The openportion of the horizontal stud faces upwardly so that the back of thehorizontal stud rests on the back of the downwardly facing uppermounting channel. As described below, the horizontal stud and the uppermounting channel are fastened together and are shown as a unit in FIGS.20 and 21. The width of the horizontal stud in the illustratedembodiment is 4 inches in the illustrated embodiment. The width of thehorizontal stud is increased to correspond to the width of the verticalstud 134 if the thickness of the blast wall assembly 110 is increased.

As further described in more detail below, the horizontal stud 142 fitswithin a downwardly facing opening in a generally M-shaped upper blasttrack 144, which is shown in more detail in FIGS. 18 and 19. Asillustrated, the upper blast track does not have a flat base. Rather, acentral portion of the base is depressed to form a generally trapezoidaldepression 146. The upper blast track is secured to the upper header 112by the upper anchor bolts 120 by an upper mounting system describedbelow. The horizontal stud and the upper mounting channel are notfixedly attached to the upper blast track and are free to move up anddown as a unit within the upper blast track. Accordingly, the engagementbetween the horizontal stud and the upper blast track provide a floatingmounting structure.

In the illustrated embodiment, the upper blast track 144 has an insidewidth of approximately 4 inches to accommodate the outside width of theupper horizontal stud 142. The inside width is increased to accommodatea wider horizontal stud if the thickness of the blast wall assembly 110is increased. The generally trapezoidal depression 146 maintains thesame size and shape even if the overall width of the upper blast trackis increased for a thicker blast wall assembly. In particular, thedepression causes the base of the upper blast track to protrudeapproximately 0.676 into the inner cavity of the upper blast track. Theprotrusion has a width within the cavity of approximately ofapproximately 2.434 inches.

As further shown in FIG. 1, the lower end of each vertical stud 134 ismounted to a lower mounting track (channel) 150, which is alsoadvantageously a modified conventional mounting channel for ametal-framed building having a structure and dimensions similar to theupper channel 140. Unlike the lower channel in a conventionalmetal-framed wall structure, the lower channel in FIG. 1 is not fixedlyattached to the lower header 114. Rather, as described below in moredetail, the lower channel is mounted to the lower header in a mannerthat allows the lower channel to move laterally. Also, the lower end ofthe vertical stud is mounted within the lower channel to allow thevertical stud to move by a limited amount within the lower channel.

In the illustrated embodiment, each of the inner blast panels 130 andthe outer blast panels 132 is generally rectangular and has a lengthgreater than the width. The blast panels are mounted on the respectiveinsides and outsides of the vertical studs with the longer dimensionmounted horizontally as shown to reduce the number of vertical seams inthe finished panels. Thus, each of the inner wall and the outer wall hasat least two courses (rows) of panels. For example, the blast wallassembly 110 illustrated in FIG. 1 has a height of approximately 8 feetand comprises two rows of panels. A twelve-foot wall advantageouslycomprises three rows of panels. As further illustrated in FIG. 1, inpreferred embodiments, the vertical seams in adjacent rows are staggeredto reduce the overall length of a continuous vertical seam. Inalternative embodiments, either the inner blast panels or the outerblast panels or both the inner blast panels and the outer blast panelsare mounted on the respective insides and outsides of the vertical studswith the long dimension oriented vertically.

As shown in more detail in FIGS. 8 and 9, for example, each inner blastpanel 130 advantageously comprises a metal sheet 160 bonded to aninterior wall board 162 using a suitable adhesive, such as, for example,an epoxy or a glue. The adhesive is cured (e.g., dried) while applyingpressure to the two layers of materials to form the laminated innerblast panel. The inner blast panel is advantageously constructed inaccordance with the technique described in U.S. Pat. No. 5,768,841,which is incorporated by reference herein. In the illustratedembodiment, the steel sheet advantageously comprises galvanized steel.The steel sheet advantageously has a thickness that ranges fromapproximately 0.0285 inch (22 gauge) to approximately 0.0713 inch (14gauge). In the illustrated embodiment, the steel sheet is advantageously20 gauge. The inner blast panels are mounted against the metal studs 134with the metal sheet against the metal studs.

In the illustrated embodiment, the interior wall board 162 has aconventional rectangular configuration with a width of approximately 4feet and has a length of approximately 8 feet; however, the interiorwall board may have other dimensions. For example, in other embodiments,the interior wall board may have a length of approximately 12 feet toreduce the number of seams between inner blast panels. In particularembodiments, the wall board comprises a highly mold-resistant interiorgypsum board, such as, for example, ⅝ inch DensArmor Plus® paperlessinterior drywall, which is commercially available from Georgia-PacificBuilding Products of Atlanta, Ga. Other suitable interior wall boardmaterials may be advantageously used.

In the preferred embodiment shown in FIG. 1, the metal sheet 160 hassubstantially the same length as the interior wall board 162. The metalsheet may also have substantially the same width as the interior wallboard; however, in the illustrated embodiment, the metal sheets of atleast the inner blast panels 130 for the lower row of panels preferablyhas a greater width. In particular, as shown in FIG. 8, a portion of themetal sheet extends beyond one of the longer edges of the wall board toform an exposed metal tab 164 having a width of approximately 1¼ inches.As further shown in FIG. 8, a panel in the upper row of panels ispositioned over the metal tabs of the panel in the next lower row ofpanels. Accordingly, when the inner blast panels are secured to themetal studs, the metal sheets form a continuous vertical diaphragmacross against the metal studs. The metal tab is not needed for theuppermost row of inner blast panels. The metal tab may be removed.Alternatively, the inner blast panels may be provided without tabs forinstallation on the uppermost rows.

As shown in FIG. 9, for example, the outer blast panel 132 has aconfiguration similar to the configuration of the inner blast panel 130.The outer blast wall advantageously comprises a metal sheet 170 bondedto an exterior wall board 172 using a suitable adhesive, such as, forexample, an epoxy or a glue. The adhesive is cured (e.g., dried) whileapplying pressure to the two layers of materials to form the laminatedinner blast panel. The outer blast panel is advantageously constructedin accordance with the technique described in U.S. Pat. No. 5,768,841,which is incorporated by reference herein. The steel sheetadvantageously has a thickness that ranges from approximately 0.0285inch (22 gauge) to approximately 0.0713 inch (14 gauge). In theillustrated embodiment, the steel sheet is advantageously 14 gauge. Inthe illustrated embodiment, the steel sheet advantageously comprises 14gauge (approximately 0.071 inch thick) galvanized steel. The outer blastpanels are mounted against the metal studs 134 with the metal sheetagainst the metal studs.

In the illustrated embodiment, the exterior wall board 172 has aconventional rectangular configuration with a width of approximately 4feet and has a length of approximately 8 feet; however, the exteriorwall board may have other dimensions. For example, in other embodiments,the exterior wall board may have a length of approximately 12 feet toreduce the number of seams between outer blast panels. In particularembodiments, the exterior wall board comprises a highly mold-resistantexterior cement board, such as, for example, ⅝ inch Durock® brand cementboard, which is commercially available from USG Corporation of Chicago,Ill. Other suitable exterior wall board materials may be advantageouslyused.

In the illustrated embodiment, the metal sheet 170 of the outer blastpanel 132 advantageously has dimensions generally corresponding to thedimensions of the exterior wall board 172; however, the metal sheet maybe wider to provide a tab (not shown) similar to the tab 164 describedabove for the inner blast panel 130.

As shown in FIGS. 8 and 9, each inner blast panel 130 is secured to theplurality of vertical studs 134 by a plurality of inner wall fasteners180. For example, in the illustrated embodiment, the inner wallfasteners advantageously comprise No. 8 Senco® Duraspin screwscommercially available from Senco Products of Cincinnati, Ohio. Theinner wall fasteners are spaced apart by a selected distance along thevertical studs. For example, in the illustrated embodiment, the innerfasteners are spaced apart by a center-to-center distance ofapproximately 6 inches. Each inner blast panel in the upper row is alsoadvantageously secured to the upper channel 140 by a plurality of theselected fasteners, which are also spaced apart by a suitable distance(e.g., 6 inches). Furthermore, the lower portion of each inner blastpanel in the upper row is fastened to the tab 164 of the inner blastpanels which the upper panel overlaps by inserting fasteners in theareas spanning between adjacent vertical studs. Each inner wall fastenerhas a flat head and is driven into the inner blast panel until the headof the fastener is flush with the exposed surface of the inner blastpanel. Thus, when the structure of the blast wall assembly 110 iscompleted, the exposed surfaces of the inner blast panels may befinished in a conventional manner so that the wall has the appearance ofa conventional wall.

As shown in FIG. 9, each outer blast panel 132 is secured to the sidewalls of a plurality of vertical studs 134 by a plurality of outer wallfasteners 190. For example, in the illustrated embodiment, the outerwall fasteners advantageously comprise a 3/16 inch or ¼ inch Kwik-Conconcrete screws commercially available from Hilti, Inc. of Tulsa, Okla.The outer wall fasteners are spaced apart by a selected distance alongthe vertical studs. For example, in the illustrated embodiment, theouter wall fasteners are spaced apart by a center-to-center distance ofapproximately 4 inches. Each outer blast panel in the upper row is alsoadvantageously secured to the upper channel 140 by a plurality of theselected fasteners, which are also spaced apart by a suitable distance(e.g., 6 inches). If the lower outer blast panels include tabs (notshown), the lower portion of each outer blast panel in the upper row isfastened to the tab of the outer blast panels which the upper paneloverlaps. Each outer wall fastener has a flat head and is driven intothe outer wall panel until the head of the fastener is flush with theexposed surface of the outer wall panel.

FIG. 2 illustrates an enlarged cross-sectional elevational view of aportion of the upper concrete header 112, the upper blast track 144, thehorizontal stud 142, the upper mounting channel 140, and the upper endsof two vertical studs 134 viewed in the direction of the lines 2-2 inFIG. 1.

FIG. 2 further illustrates an upper mounting system 200 that secures theupper blast track 144 to an upper anchor bolt 120. The mounting systemis shown in more detail in a cross-sectional end view in FIG. 5 and isalso shown in a perspective view in FIG. 10 and an elevational view inFIG. 11. As illustrated, the upper mounting system comprises a generallyU-shaped blast track anchor channel 202. The anchor channeladvantageously comprises 14 gauge steel having a thickness ofapproximately 0.071 inch. The base of the anchor channel has an insidewidth of approximately 2.434 inch, which is selected to be substantiallythe same as outside width of the trapezoidal depressed portion 146. Eachleg of the anchor channel has an inside length of approximately 0.676inch, which corresponds to the height of the protrusion within thecavity of the upper blast track. The base of the anchor channel has acircular hole 204 formed approximately in the middle. The hole has adiameter of approximately 9/16 inch to accommodate the outer diameter ofthe upper mounting anchor 120.

As shown in FIG. 18, the upper blast track 144 has a first plurality ofmounting holes 206 substantially along a center line through thedepressed portion 146. Each of the first plurality of mounting holes hasa diameter corresponding to the diameter of the hole in the blast trackanchor channel 202. The first plurality of mounting holes in the upperblast track are spaced apart by approximately 24 inches to correspond tothe spacing of the upper anchor bolts in the upper header 112. As shownin FIG. 5 for one blast track anchor channel and one upper anchor bolt,the upper blast track is positioned with the upper anchor boltpositioned through a hole in the blast track, and the blast track anchorchannel is positioned with the open portion of the U shape facing upwardso that when the blast track anchor channel is positioned with the upperanchor bolt through the hole, the blast track anchor channel ispositioned with the two legs surrounding the protruding portion of thedepressed portion of the upper blast track and with the inside of thebase of the blast track anchor channel positioned against the inner wallof the depressed portion.

The upper mounting system 200 further includes a standard washer 206 anda hex nut 208. The hex nut engages the threaded end of the upper anchorbolt 120 and secures the blast track anchor channel 202 to the upperanchor bolt. The legs of the blast track anchor channel aresubstantially perpendicular to the base of the blast track anchorchannel. The blast track anchor channel resists compression when the nutis tightened onto the upper anchor bolt. In the absence of the blasttrack anchor channel, the trapezoidal shape of the upper blast track 144would tend to flatten out as the nut is tightened. Thus, the blast trackanchor channel reinforces the upper blast track and also prevents theupper blast track from deforming.

FIG. 2 further illustrates an upper energy absorption assembly 220 thatflexibly couples the horizontal stud 142 and the upper mounting channel140 to the upper blast track 144. The upper energy absorption assemblyis shown in more detail in a cross-sectional end view in FIG. 7 and isalso shown in a perspective view in FIG. 12 and an elevational view inFIG. 13.

The upper energy absorption assembly 220 comprises a threaded rod 222having a length of approximately 8 inches. The threaded rod may bethreaded for the entire length, or, as illustrated in FIGS. 12 and 13,may be threaded only at the two ends. The threads at the upper end ofthe threaded rod engage the threads in a threaded hole 226 in an anchorwedge washer 224. As shown in FIG. 7, the anchor wedge has a generallytrapezoidal profile selected to conform to the shape and size of thedepressed portion 146 of the outer wall of the base of the upper blasttrack 144. The upper threaded portion of the threaded rod passes throughone of a second plurality of holes 230 along the centerline of thedepressed portion of the upper blast track. The second plurality ofholes are shown in FIG. 18. In the illustrated embodiment, the secondplurality of holes are spaced apart by 16 inches to correspond to thespacing of the vertical studs 134 so that an energy absorption assemblymay be positioned in the space between each pair of adjacent verticalstuds. In alternative embodiments, the energy absorption assemblies maybe positioned only in every other space between the vertical studs(e.g., every 32 inches). In further alternative embodiments, the energyabsorption assemblies may be positioned in every third space between thevertical studs (e.g., every 48 inches). The upper blast track may beformed with only the second plurality of holes needed for the selectedalternative embodiment or may be formed with holes every 16 inches asshown. Preferably, the second plurality of holes are spaced apart fromthe first plurality of holes 206 so that the adjacent holes are nocloser than 4 inches.

As shown in FIG. 7, the threaded rod 222 passes through the base of thehorizontal stud 142 and through the base of the upper mounting channel140. As illustrated in FIG. 20, the horizontal stud and the uppermounting channel include a plurality of clearance holes 232 that arespaced apart by the same distance as the second plurality of holes 230of the upper blast track 144 (e.g., 16 inches in the illustratedembodiment). In FIG. 20, a portion of the side wall is broken away toshow two of the clearance holes. The other clearance holes are hidden bythe unbroken portion of the side wall.

As further illustrated in FIGS. 7, 12 and 13, the upper energyabsorption assembly 220 further comprises a bearing washer 234 thatcomprises a generally square metal plate having sides of approximately 3inches and having a thickness of approximately ⅛ inch. The bearingwasher has a clearance hole 236 positioned substantially in the centerof the square shape. For example, the clearance hole advantageously hasa diameter of approximately 9/16 inch to accommodate the threaded rod222.

When the upper energy absorption assembly 220 is positioned on the upperblast track 144, the bearing washer 234 is mounted below the base of theupper mounting track 140. The bearing washer applies pressure to theupper mounting track. The pressure is provided by a compression spring238 that is positioned around the threaded rod between the bearingwasher and a spring cap washer 240. The spring cap washer has a centralclearance hole 242 that accommodates the lower end of the threaded rod222. The spring cap washer comprises a 2-inch diameter steel platehaving a thickness of approximately 1/16 inch. The spring cap washer issecured to the lower end of the threaded rod by a standard washer 244and a hexagonal nut 246.

In the illustrated embodiment, the compression spring 238 advantageouslycomprises a ⅜ inch diameter steel wire formed as a helical spring havinga diameter to the center of the wire of approximately 1⅝ inches andhaving approximately 7 turns. The hexagonal nut 246 is threaded onto thethreaded rod 222 to adjust the length of the spring between the bearingwasher 244 and the spring cap washer 240. For example, in theillustrated embodiment, the initial length is adjusted to approximately4 inches. The hexagonal nut may be loosened to increase the length andthereby reduce the force provided by the compression spring or tightenedto decrease the length and thereby increase the force provided by thecompression spring. The compression spring does not determine the staticposition of the upper end of the vertical stud 134. As described indetail below, the compression spring and the other elements of the upperenergy absorption assembly 220 absorb blast energy and reduce thelikelihood of a catastrophic failure of the blast wall assembly 110.

In alternative embodiments (not shown), the compression spring 238 maybe replaced by a suitable thickness of an elastic rubber flange toprovide the compression force for absorbing blast energy.

In conventional wall structures, the upper end of each vertical stud issecured to the upper mounting track via screws through the side walls ofthe mounting track that engage the side walls of the vertical stud. Asshown in FIG. 2, the upper end of each vertical stud 134 is secured tothe upper mounting track 140 and the horizontal stud 142 via an upperstud attachment blast clip 250, which is illustrated in thecross-sectional end view of FIG. 4 and which is shown in more detail inFIG. 5 and in FIG. 14. In the illustrated embodiment, the upper studattachment blast clip comprises a rectangular plate of 12 gauge steelhaving a thickness of approximately 0.104 inch. The plate has a width ofapproximately 3 inches and has a length of approximately 8 inches. Theplate is formed into an L shape having a longer leg 252 in a verticalorientation with a length of approximately 5 inches and having a shorterleg 254 in a horizontal orientation with a length of approximately 3inches. Each leg has a plurality of mounting holes 256 (e.g., 6 holes)that provide clearances for the shafts of a corresponding plurality ofmounting fasteners 258 that secure the blast clips to the vertical studand to the upper mounting track and the horizontal stud. For example,the mounting fasteners advantageously comprise self-tapping sheet metalscrews, such as, for example, 5/16 inch screws having hexagonal heads.The vertical stud, the upper mounting track and the horizontal stud mayadvantageously include drilled pilot holes positioned in alignment withthe clearance holes to reduce the effort of inserting the mountingfasteners. For example, a plurality of pilot holes 260 are shown in thejoined horizontal stud and upper mounting channel in FIG. 20. Inaccordance with this configuration, the side walls of the upper mountingtrack and the horizontal stud are unobstructed so that the horizontalstud may move freely within the upper blast track as described above.

FIG. 3 illustrates an enlarged cross-sectional elevational view of aportion of the lower concrete footer 114, the bottom channel 150, andthe lower ends of two vertical studs viewed in the direction of thelines 3-3 in FIG. 1.

As shown in FIG. 3, the lower end of each vertical stud 134 is securedto the lower mounting track 150 via a lower stud attachment blast clip270, which is illustrated in the cross-sectional end view in FIG. 4 andwhich is shown in more detail in FIG. 6 and FIG. 15. The lower studattachment blast clip also comprises steel and has a length, width andthickness similar to the length, width and thickness corresponding tothe upper stud attachment blast clip 250. The lower stud attachmentblast clip is formed into a longer vertical leg 272 and a shorterhorizontal leg 274 having similar dimensions to the upper studattachment blast clip. The lower stud attachment blast clip has aplurality of mounting holes 276 (e.g., 6 holes) in the longer verticalleg to provide clearance for the shafts of a corresponding plurality ofmounting fasteners 278.

As shown in FIG. 15, an oval-shaped mounting hole 280 is formed in thehorizontal leg 274 of the lower stud attachment blast clip 270. Forexample, in the illustrated embodiment, the mounting hole has a width ofapproximately ½ inch and has a semicircular arc at each end with aradius of ½ inch. The centers of the arcs are spaced apart byapproximately 1 inch. As shown in FIGS. 3, 4 and 6, the lower studattachment blast clip is secured to the lower end of the vertical studand is positioned with the lower anchor bolt 122 substantially in thecenter of the oval-shaped mounting hole. The length of the mounting holeallows the lower stud attachment blast clip to move laterally withrespect to the lower footer 114.

As shown in FIG. 22, the lower mounting channel 150 includes a pluralityof oval-shaped mounting holes 290 having dimensions corresponding to thedimensions of the mounting hole 280 in the lower stud attachment blastclip 270. The mounting holes in the lower mounting channel are spacedapart by the selected spacing of the vertical studs 134 (e.g., 16 inchescenter-to-center in the illustrated embodiment). The lower mountingchannel is positioned over the lower anchor bolts 122 first and then thelower stud attachment blast clips for the vertical studs are positionedover the lower anchor bolts.

The lower mounting channel 150 and the lower stud attachment blast clip270 are secured to the lower anchor bolt by placing a lower blastabsorption pad 300 on the lower anchor bolt above the lower leg 274 ofthe lower attachment blast clip as shown in FIGS. 3, 4 and 6. Asillustrated in more detail in FIG. 16, the lower blast absorption padadvantageously comprises a block 302 of an elastomer, such as, forexample, ethylene propylene diene monomer (EPDM) rubber. In theillustrated embodiment, the elastomer block has a rectangular crosssection in the plan view (e.g., looking from the top) with a width ofapproximately 2 inches and a length of approximately 4 inches. Thelength is advantageously increased when a wider lower mounting channelis used for a thicker wall. The elastomer block has a thickness ofapproximately 1.25 inches and has a substantially rectangular face inthe end elevational view. In the preferred embodiment, the lower cornersof the rectangular face are chamfered to accommodate any reduction inthe channel width caused by rounding or filleting at the intersectionsof the vertical walls and the base of the lower mounting channel.

The elastomer block 302 has a bore 304 that is centrally located throughthe rectangular upper surface and that extends vertically through theblock. In the illustrated embodiment, the vertical bore has a diameterof approximately 9/16 inches to accommodate the diameter of the loweranchor bolt 122.

The elastomer block 302 further includes a plurality of horizontal bores306 that extend through the block orthogonal to the vertical bore 304.For example, in the illustrated embodiment, the block includes fourhorizontal bores with two bores located on either side of the verticalbore. The horizontal bores advantageously have diameters ofapproximately ½ inch. The absence of the EPDM material in the horizontalbores reduces the force required to compress the elastomer block.

As further shown in FIG. 16, the lower blast absorption pad furtherincludes a rectangular metal plate 310 having rectangular dimensions inthe plan view substantially similar to the rectangular dimensions of theupper surface of the elastomer block 302. The metal plate advantageouslycomprises 20 gauge steel having a thickness of approximately 0.0375inch. The rectangular metal plate includes a central circular hole 312having substantially the same diameter as the vertical bore 304 of theelastomer block.

As shown in the assembled view of the lower blast absorption pad 300 inFIG. 17, the rectangular metal plate 310 is bonded to the upper surfaceof the elastomer block 302 with the edges substantially in alignmentwith the edges of the elastomer block and with the central circular hole312 substantially aligned with the vertical bore 304. The metal plate isadvantageously bonded to the elastomer block using epoxy, glue oranother suitable adhesive.

As shown in FIG. 6, for example, the lower blast absorption pad 300 ismounted in the lower mounting channel 150 with the lower anchor bolt 122passing through the vertical hole 304 and the circular hole 312 and withthe rectangular metal plate 310 facing upward. The lower blastabsorption pad is secured to the lower anchor bolt by a standard washer320 and a hexagonal nut 322. The nut is tightened onto the lower anchorbolt to partly compress the elastomer block 302 to provide sufficientpressure so that the lower mounting channel and the lower end of thevertical stud 134 do not move when ordinary pressure is applied to theinner or outer surface of the blast wall assembly 110.

The blast wall assembly 110 and the components described above form anintegrated system that effectively absorbs blast energy. Unlikeconventional systems, the components of the blast wall assembly functionin a manner similar to highway “crumple zones” by absorbing the energygenerated by the sudden impact of a blast wave on the exterior surfaceof the blast wall. The components of the blast wall assembly flex, move,compress, crush and bend before the full magnitude of the blast load istransmitted via the components to the fasteners used to secure theassembly to the structure. By absorbing the sudden impact of energy, thesystem greatly reduces the likelihood of component failure and fastenerfailure. Although the blast wall assembly may incur repairable damage,the blast wall assembly absorbs a substantial portion of the blastenergy rather than imploding into the interior space of the structure.Thus, the blast wall assembly greatly enhances the safety of thebuilding structure and the occupants of the building structure.

When a blast pressure wave first impacts the exterior blast board, theexterior blast board (the outer blast panel 132) resists penetration byobjects, such as rocks and shrapnel, which may be hurled against thewall by the blast force. A portion of the energy of the blast wave isabsorbed by flexural bending of the exterior blast board. The loadapplied to the exterior blast board by the blast pressure wave istransferred to the vertical wall studs 134. The exterior blast boardalso provides lateral bracing for the vertical studs, which helpsprevent torsional failure of the light gauge vertical studs. Theexterior blast board also serves as a substrate for a variety ofexterior finish systems that may be applied to the cementitious wallboard forming the outer face of the exterior blast board. Thus, from theoutside, the blast wall assembly 110 may be configured to have thecosmetic appearance of a conventional wall.

The light gauge (e.g., 16 gauge) vertical wall studs 134 are flexible.Thus, when the load from the blast pressure wave is applied to the wallstuds via the outer blast panel 132, the wall studs bend and deform andeventually stretch. The magnitude of deformation of the wall studs mayexceed the yield strength of the wall studs and cause a portion of thedeformation to be permanent. The bending, deformation and stretching ofthe studs absorbs additional blast energy.

As each vertical wall stud 134 deforms inward away from the blast force,the stud has a tendency to pull out of the upper mounting channel 140and the lower mounting channel 150 that constrain the upper end and thelower end, respectively, of each stud. The angle clip (the upper studattachment blast clip 250) at the top of each vertical stud and theangle clip (the lower stud attachment blast clip 270) at the bottom ofeach stud resist this pull-out force. In particular, the top angle clipand the bottom angle clip for each stud resist disengagement of the studfrom the upper mounting channel and the lower mounting channel whilesimultaneously absorbing blast energy. As the vertical stud deflectsinwardly, the chord distance between the top end and the bottom end ofthe stud shortens. The horizontal legs 254, 274 of the angle clipsdeform by bending in response to the tensile force that attempts tostraighten the angle clips. The deformations of the angle clips absorbadditional blast energy.

When the bottom angle clip (the lower stud attachment blast clip 270)deforms, the tendency of the bottom angle clip to straighten is resistedby the bottom energy absorbing pad 300. The bottom energy absorbing padis compressed vertically as the horizontal leg 274 attempts to pull awayfrom the lower mounting channel 150. The compression of the bottomenergy absorbing pad absorbs additional blast energy. The metal plate310 laminated to the top of the bottom energy absorbing pad helpsprevent the pad from pulling over an anchor bolt 120 at the bottom ofthe wall and prevents the pad from being crushed by the hexagonal nut322 that secures the pad to the bottom attachment anchor bolt.

The bottom energy absorbing pads 300 at the bottoms of the wall studsalso absorb energy while allowing the entire base of the wall to moveinward away from the blast. As described above, the bottom mountingchannel (or track) 150 and the bottom clips (the lower stud attachmentblast clip 270) include respective slots (or oversized holes) 290, 280that permit the entire lower portion of the blast wall assembly 110 tomove inward away from the blast force until reaching the end of the slotor the boundary of the oversized hole. The bottom energy absorbing padsprevent the wall from moving too quickly and applying a shock load tothe lower anchor bolts 120. When the bottom energy absorbing padscompress under load, the pads create a more gradual (cushioned) increasein the load to the wall anchors. Thus, the bottom energy absorbing padshelp preserve the integrity of the critical attachment of the wall tothe building structure.

The upper mounting system 200 and the upper energy absorbing assembly220 at the top of the blast wall assembly 110 absorb blast energy andresist destructive movement caused by the blast energy. The uppermounting system and the upper energy absorbing assembly also permit thefloor above the blast wall assembly to deflect vertically in response tochanging live loads to the floor above the wall, the floor below thewall or both. The floating configuration of the upper mounting allowsdeflections to occur without transferring axial loads (e.g., bearingloads) to the wall. The blast wall assembly disclosed herein can be usedas either a non-bearing partition wall or as a curtain wall.

When a top angle clip (the upper stud attachment blast clip 250)deforms, the tendency of the clip to straighten is reduced by thebending of the horizontal flange stud 142 that spans the approximately24-inch spacing between adjacent upper mounting systems 200. The tensileforce caused by a blast causes the angle clip to bend (e.g., straighten)and induces weak axis bending in the horizontal flange stud. Thehorizontal flange stud also provides an engagement between the verticalwall studs and the upper blast track 144. In particular, the outersurfaces of the vertical walls of the horizontal flange stud ride mayfloat up or down within the cavity formed by the upper blast track. Thefloating engagement between the horizontal stud and the upper blasttrack is configured to reduce the effect of the blast forces. Asdescribed above, the top angle clip and the horizontal flange stud arenested so that the side walls of the horizontal flange stud areunobstructed within the upper blast track to thereby accommodatevertical movement between the floor above and the wall below. Additionalblast energy is absorbed by bending of the horizontal stud flange andbending of the flange of the upper blast track on the side of the wallopposite the blast. Both components bend in a direction normal to theplane of the wall.

Lateral movement of the blast wall assembly 110 in a direction normal tothe wall plane is primarily resisted by bending of a down-turned flangeof the upper blast track 144. As each vertical stud 134 bends, the chorddistance between the upper and lower ends of the vertical stud shortensas discussed above. The spring 238 or other elastic member in the upperenergy absorption assembly 220 compresses to absorb blast energy. Oncethe spring in the energy absorbing assembly is fully compressed, thethreaded steel rod 222 in the assembly transmits tensile loads to theupper blast track through the anchor wedge washer 224 described above.As the wall deforms inward, the threaded rod pivots to transfer tensileload and shear load to the upper blast track, which causes the upperblast track to deform in the vicinity of the wedge washer. Thedeformation of the upper blast track absorbs more blast energy.

Once the blast load is transferred to the upper blast track 144 bybending the outer wall (the flange of the upper blast track) and by theupper energy absorption assembly 220, the transferred load istransferred to the building structure by way of the upper anchor bolt120 embedded in the concrete header 112. The force transferred to theupper anchor bolt is cushioned by the deformation of the trapezoidalchannel (the depressed portion 146) in the upper blast track and by thevertical flange and weak axis bending of the U-shaped blast track anchorchannel 202. The shape of the blast track in combination with the blasttrack anchor channel results in a more gradual transfer of forces to thetop connection, which helps preserve the integrity of the top connectionand of the blast wall assembly 110.

The blast wall assembly further comprises an interior blast board (theinner blast panels 130). Each panel of the interior blast boardcomprises a layer of metal 160 and an interior finish wall board 162 toform a generally rectangular sheet. In the illustrated embodiment, theinterior blast board is fabricated with a metal flange 164 extendingalong one of the long edges. The long edges are oriented horizontally inthe preferred embodiments. The metal flange allows the interiorsheathing to be spliced to the adjacent sheathing (the inner blast panelimmediately above). The splice effectively connects the upper and lowersheathing boards to form a continuous protective curtain reaching fromthe top to the bottom of the wall. If one or more sheets becomedislodged, the dislodged sheets remain in place on the wall and pose nohazard to the building occupants. Preferably, the sheets are positionedon the wall with the locations of the splices staggered so that thesplices do not coincide with the utility punch outs in the verticalstuds of the wall. Thus, the interior blast board reinforces the walland helps prevent stud failure at the utility punch-outs. Furthermore,the metal lined interior blast boards provide torsional restraint forthe vertical studs 134 to effectively prevent torsional failure of thevertical studs. In alternative embodiments, the panels of the interiorblast wall are mounted with the long edges oriented vertically. In thevertically oriented embodiment, the panels can be manufactured withoutthe metal flange along the long edge since the seams between panels willbe on a vertical stud.

FIG. 24 illustrates a perspective view of portion of a wall section 500in accordance with a further embodiment of an energy absorbing blastwall positioned between the upper header 112 and the lower footer 114.FIG. 25 illustrates an enlarged cross-sectional plan view of the portionof the wall section in FIG. 24 viewed in the direction of the lines25-25 in FIG. 24. As shown in FIG. 25, a plurality of cavities 510formed between inner blast panels 512 and outer blast panels 514, whichare mounted on a plurality of C-studs 516. The inner and outer blastpanels are preferably constructed as described above with respect toFIGS. 8 and 9.

In FIGS. 24 and 25, the C-studs 516 in the wall section 500 are mountedin a conventional manner with the main body portions (webs) 520 of theC-studs perpendicular to the inner blast panels 512 and the outer blastpanels. The blast panels are mounted to the opposing side walls (mainflanges) 522 of the C-studs. The thickness of the cavity formed betweenthe inner and outer blast panels is determined by the length of the websof the C-studs and can vary from 3.5 inches to 10.5 inches in accordancewith a selected overall thickness of the wall section. Thecenter-to-center spacing between adjacent C-studs is advantageouslyselected to be 16 inches; however, the spacing can be modified ifdesired. For example, as discussed above, the C-studs can be spacedapart by 12 inches for greater blast strength. The wall sectionillustrated in FIGS. 24 and 25 advantageously has a width ofapproximately 48 inches, a height of approximately 96 inches andthickness of approximately 6 inches. With the illustrated 16-inchcenter-to-center spacing, three cavities are formed in the wall section.The blast panels may be mounted on the studs with the long edgesoriented horizontally as described above in order to interconnectadjacent wall sections (not shown). However, in the embodimentsillustrated in FIGS. 24-35, at least one, and preferably both, of theinner and outer blast panels are mounted on the C-studs with the longedges of the blast panels oriented vertically. In such embodiments, theblast panels are preferably mounted so that the seams between adjacentblast panels are aligned with one of the two middle C-studs (when thespacing is 16 inches) rather than being aligned with the seams jointbetween adjacent wall sections so that the blast panels span the abuttedjoint between adjacent wall sections. By staggering the blast panelswith respect to the wall sections in the alternative embodiment, theblast panels assist in interconnecting adjacent wall sections. Asfurther illustrated in FIG. 25, the vertical seam 526 between adjacentinner blast panels and the vertical seam 528 between adjacent outerblast panels are staggered with respect to each other.

Each of the cavities 510 in the wall section 500 is substantially filledwith an energy absorbing material 530 that also serves as an insulatingmaterial. For example, in an exemplary embodiment, the energy absorbingmaterial advantageously comprises expanded polystyrene (EPS) foam. Theenergy absorbing material may be added during the erection of the wallsection by filling each cavity with heated, flowable material andallowing the material to cool to a solid form. In certain preferredembodiments, the energy absorbing material and the C-studs 516 areformed by mass production techniques (e.g., in a factory) with the foamadhered to the C-studs using a heat-reactive adhesive. After erectingthe factory-built panel section with the C-studs positioned between anupper track assembly 540 and a lower track assembly 542, as describedabove, the inner blast panels 512 and the outer blast panels 514 aresecured to the flanges 522 of the C-studs, as described above. As shownin FIG. 25, the C-stud at each end of the wall section is mounted flushwith the edge of the wall section. Furthermore, a C-stud at one end ofthe wall section is mounted in the opposite orientation to the otherC-studs. This configuration allows each wall section to fully enclosethe cavities. In this configuration, adjacent wall sections are mountedwith main body portions of the end C-studs of each wall sectionback-to-back with the main body portions of the end C-studs of adjacentwall sections.

In FIG. 24, the upper track assembly 540 and the lower track assembly542 are mounted to the upper header 112 and the lower footer 114,respectively, and are constructed as described above to provide theadvantageous energy absorbing characteristics also described above. Aportion of the energy absorbing material 530 filling the cavities isremoved to provide clearance for the components that extend into thecavities from the upper track and the lower track. In embodiments wherethe energy absorbing material is added at the construction site, thecomponents extending into the cavities can be shrouded during thefilling process.

In a further embodiment illustrated in FIGS. 26 and 27, a wall section600 is constructed as described above in connection with FIGS. 24 and25; however, the C-studs 516 in FIGS. 26 and 27 are mounted to aconventional fixed upper track assembly 610 and a conventional fixedlower track assembly 612, which are mounted directly to the upper header112 and the lower footer 114, respectively.

FIG. 28 illustrates a perspective view of portion of a wall section 700in accordance with a further embodiment of an energy absorbing blastwall. FIG. 29 illustrates an enlarged cross-sectional plan view of theportion of the wall section in FIG. 28 viewed in the direction of thelines 29-29 in FIG. 28. The embodiment of FIGS. 28 and 29 is similar tothe embodiment of FIGS. 24 and 25; however, as shown in FIG. 29, asingle cavity 710 is formed between inner blast panels 712 and outerblast panels 714. As described above, the inner and outer blast panelsare preferably mounted with the long edges in a vertical orientation,with a respective vertical seam 716 between adjacent inner blast panelsand a respective vertical seam 718 between adjacent outer blast panels.As shown in FIG. 29, the vertical seam between outer blast panels isstaggered with respect to the vertical seam between inner blast panels.Neither vertical seam coincides with a joint between adjacent wallsections so that the inner and outer blast panels span between andthereby interconnect adjacent wall sections. Unlike the previouslydescribed embodiment, the inner blast panels and the outer blast panelsare mounted on the main body portions (webs) 724 of a first plurality720 of U-channel studs and a second plurality 722 of U-channel studs,respectively. The side walls (flanges) 726 of the U-channel studs extendinto the cavity perpendicular to the respective blast panels. Thus, theside walls are embedded in the energy absorbing material 730 that fillsthe cavity between the inner and outer blast panels.

As illustrated in FIG. 29, the first plurality 720 and the secondplurality 722 of U-channel studs are spaced apart by a selected distanceto provide a selected thickness for the cavity 710 between the innerblast panels 712 and the outer blast panels 714. For example, thethickness may vary from 3.5 inches to 10.5 inches in certainembodiments. The thickness of the cavity and thus the spacing betweenthe inner and outer blast panels is determined by the thickness of theenergy absorbing material 730 that fills the cavity. Preferably, theU-channel studs and the energy absorbing material are formed in mold ortemplate in a factory setting so that the thickness is readilycontrollable to a desired specification. As described above, the energyabsorbing material may be any energy absorbing material and isadvantageously expanded polystyrene (EPS) foam in certain embodiments.

As further illustrated in FIG. 29, the first plurality 720 of U-channelstuds is offset from the second plurality 722 of U-channel studs byapproximately 1 inch in the horizontal direction. The energy absorbingmaterial 730 is shaped so that the portion of the material proximate thefirst plurality of U-channel studs and the inner blast panels 712 isoffset by a corresponding amount so that the energy absorbing materialextends between respective outermost sidewalls 726 of the firstplurality of U-channel studs. Similarly, the portion of the materialproximate the second plurality of U-channel studs and the outer blastpanels 714 is offset by a corresponding amount so that the energyabsorbing material extends between respective outermost sidewalls of thesecond plurality of U-channel studs. As a result of the offsets, at oneend of the energy absorbing material, a portion 740 proximate the innerblast panels extends farther than a portion 742 proximate the outerblast panels. At the other end of the energy absorbing material, aportion 750 proximate the outer blast panels extends farther than aportion 752 proximate to the inner blast panels. Preferably, the twoportions of the energy absorbing material are divided substantiallyequally along a horizontal centerline 760 so that the two portions havesubstantially the same thickness. Accordingly, when two wall sectionsare abutted, the extended portions of the energy absorbing material ofone wall section are juxtaposed with the unextended portions of theenergy absorbing material of the other wall section so that adjacentwall sections form a shiplap structure. Furthermore, each wall structureis rotationally symmetric such that each section of energy absorbingmaterial with the embedded U-channel studs may be installed with eithersurface facing either the inner blast walls or the outer blast walls.

The wall section 700 of FIGS. 28 and 29 with the U-channel studs 720,722 and the shiplap cavity structure 730 may be installed with the upperenergy absorbing track assembly 540 and the lower energy absorbing trackassembly 542 as described above. Alternatively, as shown in FIGS. 30 and31, a wall section 750 with the U-channel studs and the shiplap cavitystructure may be installed in combination with the fixed upper track 610and the fixed lower track 612.

FIGS. 32 and 33 illustrate a wall section 800 similar to the embodimentof FIGS. 28 and 29; however, in FIGS. 32 and 33, a cavity 810 is formedbetween inner blast panels 812 and outer blast panels 814, which aremounted on a first plurality 820 of C-studs and a second plurality 822of C-studs, respectively. The C-studs in FIGS. 32 and 33 replace thecorresponding U-channel studs in FIGS. 28 and 29. As described above,each C-stud comprises a main body portion (web) 824, opposing side walls(main flanges) 826 and smaller flanges (lips) 828, which areperpendicular to the side walls. The cavity between the inner and outerblast panels is filled with energy absorbing material 830, as describedabove. The C-studs are mounted with their respective main body portionsagainst the respective blast panels. The side walls (main flanges) ofthe C-studs extend into the energy absorbing material and the smallerflanges (lips) of the C-studs extend further into the energy absorbingmaterial perpendicular to the side walls to provide additionalengagement between the C-studs and the energy absorbing material. TheC-studs on opposing sides of the energy absorbing material are offsethorizontally as described above, and the energy absorbing material isformed with the shiplap structure, described above in connection withFIGS. 28 and 29. As described above, the inner and outer blast panelsare preferably mounted with the long edges in a vertical orientation,with a respective vertical seam 840 between adjacent inner blast panelsand a respective vertical seam 842 between adjacent outer blast panels.As shown in FIG. 33, the vertical seam between outer blast panels isstaggered with respect to the vertical seam between inner blast panels.Neither vertical seam coincides with a joint between adjacent wallsections so that the inner and outer blast panels span between andthereby interconnect adjacent wall sections.

In FIGS. 32 and 33, the wall section 800 is mounted between the upperenergy absorbing track assembly 540 and the lower energy absorbing trackassembly 542. FIGS. 34 and 35 illustrate the corresponding wallstructure 850 mounted between the fixed upper track assembly 610 and thefixed lower track assembly 612.

In the above-described embodiments, the blast wall sections areinstalled between an upper header 112 and a lower footer 114. Inalternative embodiments, the blast wall sections can also be installedas curtain walls which hang on the outside of the building structure andspan across the floors. FIG. 36 illustrates the wall section 850 of FIG.34 installed as a portion of a curtain wall that spans from an upperbeam 870 to a lower beam 872. Rather than being mounted between the twobeams, the wall section is mounted to the outer face of each beam asshown using suitable mounting hardware (not shown). The other wallsections disclosed herein can be similarly adapted to be installed assections of a curtain wall.

FIG. 37 illustrates a cross-sectional view of an alternative wallsection 900, which is similar to the wall sections illustrated in thecross-sectional views of FIGS. 33 and 35; however, in FIG. 37 theC-studs are replaced with a modified set of studs comprising a pluralityof double-lipped (hat channel) studs 910 and a plurality ofsingle-lipped studs 912. In particular each of the double-lipped studshas a respective web 920 and first and second outer flanges 922perpendicular to the web. Each of the outer flanges has a respective lip924 perpendicular to the respective flange and facing outward (away fromthe center of the stud) from the respective flange. In an illustratedembodiment, the web of the stud has a width of approximately 4 inches,each outer flange has a length of approximately 1.5 inches, and each liphas a length of approximately 1 inch. Each stud advantageously comprisesgalvanized steel having a thickness in a range corresponding to a rangefrom 18 gauge to 12 gauge.

The single-lipped studs 912 are similar to the double-lipped studs 910.Each single-lipped stud has a respective web 930 and first lipped outerflange 932 and a second unlipped outer flange 934 orientedperpendicularly to the web. The lipped outer flange has a lip 936 whichis directed outwardly (away from the center of the stud) as describedabove for the double-lipped stud. The unlipped outer flange) does nothave a lip.

As shown in FIG. 37, a respective one of the single-lipped studs 912 ispositioned at each end of the wall section 900 with the unlipped outerflange 934 aligned with the respective end of formed energy absorbingmaterial 940 between an inner blast panel 942 and an outer blast panel944. The respective web 930 of each single-lipped stud is positionedagainst the respective blast panel with the unlipped flange and thelipped flange 932 extending into the energy absorbing material. Thesingle lip 936 extends from the lipped flange into the energy absorbingmaterial.

The double-lipped studs 910 are positioned with their respective webs920 positioned against one of the inner blast panel 942 or the outerblast panel 944. Each double-lipped stud is positioned with the respectto the single-lipped studs 912 so that the center of each double-lippedstud is approximately 16 inches from the unlipped outer flange 934 ofthe adjacent single-lipped stud at the nearest end of the wall section.Accordingly, for a wall section 900 having a nominal width of 48 inches,two double-lipped studs are disposed between each single-lipped stud.The width of the wall section and the spacing between studs can bevaried for different applications. The spacing between the inner blastpanel and the outer blast panel can also be varied in accordance with adesired wall thickness.

In FIG. 37, the energy absorbing material 940 between the inner blastpanel 942 and the outer blast panel 944 is formed with the offsets ateach end to form the shiplap shape described above. Accordingly, thestuds adjacent the inner blast panel are staggered with respect to thestuds adjacent the outer blast panel, as described above.

FIG. 38 illustrates a further embodiment of a wall section 950, which issimilar to the wall section 900 in FIG. 37. Accordingly, like elementsare numbered as in FIG. 37. As discussed above, the energy absorbingmaterial 940 in the wall section of FIG. 37 is formed with a shiplapconfiguration. The wall section of FIG. 38 includes energy absorbingmaterial 960 that does not include the offset between the portionadjacent an inner blast panel 962 and an outer blast panel 964.Accordingly, the unlipped outer flanges 934 of the single-lipped studs912 at each edge of the wall section are aligned rather than beingstaggered. Similarly, the double-lipped studs 910 adjacent the innerblast panel are aligned with corresponding double-lipped studs adjacentthe outer blast panel.

The embodiments of FIGS. 37 and 38 are advantageous in providingadditional surface area of the studs 910, 912 in contact with the energyabsorbing material 940, 960 to provide increased adhesion between thestuds and the energy absorbing material.

In FIGS. 37 and 38, one or both of the respective inner blast panels942, 962 and the respective outer blast panels may be installed with therespective long edges of the panels oriented horizontally or orientedvertically, as discussed above.

FIG. 39 illustrates a perspective view of a blast wall 1000 similar tothe blast wall 100 of FIG. 1 but with a lower track (channel) 1010having integral tabs 1012 for connecting to the vertical studs 134. FIG.40 illustrates an enlarged perspective view of a portion of the lowertrack and the vertical stud at the location of the tab. As shown in FIG.40, the tab extends substantially perpendicularly from the webbing 1014of the lower track. Preferably, the tab includes a pilot hole 1016 (seeFIG. 44) into which a sheet metal screw 1020 is inserted and thenrotated to engage the lower end of the webbing 1030 of the vertical studpositioned adjacent to the tab. The tab replaces the lower studattachment blast clip 270 shown in FIG. 3. In a further embodiment (notshown), each upper stud attachment blast clip 250 can also be replacedby a corresponding tab (not shown) formed in the upper track in themanner described below. The lower track in FIGS. 39 and 40 isadvantageously used in combination with the lower blast absorption pad300 (shown in phantom in FIG. 40); however, each lower anchor bolt 122passes only through the blast absorption pad and a mounting hole 1032 inthe webbing of the channel. In the illustrated embodiment, the mountingholes are round. The mounting holes may also be oval-shaped as describedabove in connection with the embodiment shown in FIG. 22.

In one embodiment of the lower track 1010 in accordance with FIGS. 39and 40, each tab 1012 and pilot hole 1016 are formed in the webbing 1014during the manufacturing of the track by stamping or other suitableprocess. In particular, a generally U-shaped slot 1040 is formed in thewebbing along with the pilot hole as shown in FIGS. 41 and 42. Themounting holes 1032 may be formed in the webbing during the sameprocess. The slots are spaced apart by the desired spacing of thevertical studs 134 (e.g., 16 inches) and are displaced from the slots bya selected distance. The mounting holes can be spaced apart by similardistances as shown in FIG. 41; however, in the illustrated embodimentthe anchor bolts 122 and blast absorption pads 300 are not used tosecure the vertical studs to the webbing. Thus, it is not necessary toinsert an anchor bolt and a blast absorption pad at the location of eachmounting hole.

FIG. 43 illustrates a perspective view of the second stage ofconstruction of the lower track 1010 of FIG. 41 showing the tabs 1012bent upward from the webbing 1014 to a position substantiallyperpendicular to the webbing. FIG. 44 illustrates an enlargedperspective view one of the tabs.

The embodiment of FIGS. 39-44 advantageously provides additional blastprotection by interconnecting the webbing 1030 of each vertical stud 134with the webbing 1014 of the lower track 1010 without requiring theadditional hardware of the lower stud attachment blast clip 270 for eachstud. As discussed above, the upper stud attachment blast clips 250 mayalso be replaced by forming corresponding tabs in an upper track (notshown).

FIG. 45 illustrates a perspective view of a blast wall 1100 similar tothe blast wall 100 of FIG. 1 but with a lower track 1110 having a lowerstud attachment clip 1112 attached to the webbing 1114 of the verticalstud 134 and also attached directly to the webbing 1116 of the lowertrack. FIG. 46 illustrates an enlarged perspective view of a portion ofthe lower track and the vertical stud proximate to the location of theintersection of the stud with the lower track.

As illustrated in FIGS. 45 and 46, the lower stud attachment clip 1112is mounted to the webbing 1114 of the stud 134 as described above usinga plurality of self-tapping screws 1120. For example, the lower studattachment clip is advantageously mounted to the stud prior toinstallation with the stud lying horizontally so that the screws do nothave to be driven horizontally by the installer when the stud is in avertical position. After positioning the stud, the horizontal leg of thelower stud attachment clip is secured to the webbing 1116 of the lowertrack 1110 by a plurality of screws 1122, as illustrated, or by weldingthe horizontal leg to the webbing, or by attaching the horizontal leg tothe webbing using power-driven pins. When screws or pins are used, thescrews or pins are also driven into the concrete of the underlying lowerfooter 114.

As further illustrated in FIGS. 45 and 46, the lower track 1110 issecured to the lower footer 114 using the anchor bolts 122 as before;however, in the embodiment of FIGS. 45 and 46, a steel plate 1130 ispositioned beneath the washer 320 and nut 322 so that when the nut istightened on the anchor bolt, the steel plate secures the webbing 1116of the lower track against the lower footer. In the illustratedembodiment, the steel plate is flat and is generally rectangular. Therectangular dimensions of approximately 4 inches by 2 inches for a4-inch lower track so that the steel plate fits within the lower track.The steel plate advantageously has a thickness of approximately 0.25inch. During a blast event, the steel plate at each anchor bolt protectsthe relatively thin webbing of the lower track from stresses caused byforces that would otherwise bend the webbing in the locations of theanchor bolts. Unlike the embodiment of FIG. 1, the embodiment of FIGS.45 and 46 advantageously allows the installer to position the studs 134independently of the locations of the anchor bolts to provide additionalflexibility in selecting positions for the studs and the anchor bolts.

One skilled in art will appreciate that the foregoing embodiments areillustrative of the present invention. The present invention can beadvantageously incorporated into alternative embodiments while remainingwithin the spirit and scope of the present invention, as defined by theappended claims.

1-6. (canceled)
 7. A wall system for protecting a building structurefrom pressure caused by explosive blasts, comprising: a plurality ofvertical studs having respective upper ends and lower ends; at least oneouter blast wall panel secured to the vertical studs to form an outerwall of the wall system; at least a first inner blast wall panel and asecond inner blast wall panel, at least the first inner blast wall panelincluding an extended tab; a plurality of fasteners that secure thefirst inner blast wall panel and the second inner blast wall panel tothe vertical studs to form an inner wall of the wall system, theextended tab of the first inner blast wall panel positioned between aportion of the second inner blast wall panel and the vertical studs suchthat selected ones of the plurality of fasteners extend through theportion of the second inner blast wall panel and the extended tab of thefirst inner blast wall panel to interconnect the first inner blast wallpanel and the second inner blast wall panel; an upper mounting systemattached to the building structure, the upper ends of the vertical studsattached to the upper mounting system; and a lower mounting systemattached to the building structure, the lower ends of the vertical studsattached to the lower mounting system.
 8. The wall system as defined inclaim 7, wherein: each of the first inner blast wall panel and thesecond inner blast wall panel is configured as a rectangle having firstand second parallel sides longer than third and fourth parallel sides,the third and fourth parallel sides orthogonal to the first and secondparallel sides; the extended tab of the first inner blast wall ispositioned along the first parallel side of the first inner blast wall;and the first inner blast wall panel and the second inner blast wallpanel are mounted on the vertical studs with the respective first andsecond parallel sides in a horizontal orientation, with the respectivethird and fourth parallel sides in a vertical orientation, and with theportion of the second parallel side of the second inner blast wall paneloverlapping the extended tab of the first inner blast wall panel.
 9. Thewall system as defined in claim 7, wherein: each of the first innerblast wall panel and the second inner blast wall panel comprises agenerally rectangular metal sheet and an interior wall board laminatedto the metal sheet; each of the first inner blast wall panel and thesecond inner blast wall panel is secured to the vertical studs with themetal sheet positioned against the vertical studs and with the interiorwall board facing away from the vertical studs; and the extended tab ofthe first inner blast panel is an extension of the rectangular metalsheet of the first inner blast panel.
 10. The wall system as defined inclaim 7, wherein the upper mounting system comprises an energy absorbingsystem that allows the upper ends of the vertical studs to elasticallymove with respect to the building structure while remaining attached tothe upper mounting system.
 11. The wall system as defined in claim 7,wherein: the lower mounting system comprises a lower track having awebbing; the respective lower end of each vertical stud is attached tothe lower track with a respective attachment device, the attachmentdevice comprising a respective L-shaped attachment clip that secures thelower end of the vertical stud to the webbing of the lower track; and aplurality of plates secure the webbing of the lower track to acorresponding plurality of anchor bolts to secure the lower track to alower footing into which the anchor bolts are embedded.